Process and apparatus for separation of mineral ore from gangue material

ABSTRACT

A process and apparatus for breaking the mechanical bonds between relatively interlocked and embedded mineral ore crystals and gangue crystals are disclosed. Severing the bonds between the crystals is effected by irradiating the rock material with ultrasonic waves in the range of about 300,000 to about 1,200,000 cycles per second. The frequency of the ultrasonic waves is selected to cause one of the ore and gangue crystals to vibrate at about a resonant frequency thereof until oscillations within the resonating crystals and a node condition at the interfaces between crystals causes fracturing of the rock material at about the interfaces. The separation of magnetite and rutile crystals, as contained in black sands material, by ultrasonic irradiation is particularly advantageous, and a magnetic concentrator and separator capable of separation of ferromagntic and nonferromagnetic particles in a liquid medium is also disclosed.

United States Patent [191 Speer 1 May 21, 1974 2 Filed PROCESS ANDAPPARATUS FOR SEPARATION OF MINERAL ORE FROM GANGUE MATERIAL Inventor:Rolland Orin Speer, 2254 Wordside Ln. Apt. 6, Sacramento, Calif. 95825Dec. 4, 1972.

Appl. No.: 312,232

References Cited UNITED STATES PATENTS 7/1962 Burgess 241/1 X 4/1961Kececioglu et a1. 241/1 l0/l959 Sasaki 24l/l X 11/1955 Myers 24l/l XChickering 57 ABSTRACT A process and apparatus for breaking themechanical bonds between relatively interlocked and embedded mineral orecrystals and gangue crystals are disclosed.

Severing the bonds between the crystals is effected byirradiating therock material with ultrasonic waves in the range of about 300,000 toabout 1,200,000 cycles per second. The frequency of the ultrasonic wavesis selected to cause one of the ore and gangue crystals to vibrate atabout a resonant frequency thereof until oscillations within theresonating crystals and a node condition at the interfaces betweencrystals causes fracturing of the rock material at about the interfaces.The separation of magnetite and rutile crystals, as contained in blacksands material, by ultrasonic irradiation is particularly advantageous,and a magnetic concentrator and separator capable of separation offerromagntic andnon-ferromagnetic particles in a liquid medium is alsodisclosed.

PATENTEBMY 2 1 1974 SHEET 1 [1F 2 PROCESS AND APPARATUS FOR SEPARATIONOF MINERAL ORE FROM GANGUE MATERIAL BACKGROUND OF THE INVENTION Everyyear enonnous quantities of mineral bearing alluvial sands are depositedin river delta areas. Certain of these alluvial sands and deposits areknown to be very rich in iron ore and titanium. These alluvial sanddeposits are commonly referred to as black sands, and they occur inextremely large deposits along the Pacific Coast of the United States,New Zealand, Australia, South Africa, South America and Korea, to name afew locations.

Considerable effort has been made in connection with attempts to recoverthe highly useful iron ore, found in the black sands as magnetite (Fe Oand the titanium ore, found in the black sands as rutile (TiO It hasbeen predicted that by the year 2,000 the demand for primary metals willhave increased about four times over the present needs; therefor, thepressure to recover iron and titanium from black sands has and iscontinually mounting.

Attempts were made as early as 1849 to smelt black sands. A hightitanium content in iron ore, however, hampers blast furnace operations,and more than two percent by weight of titanium will make the oreunsuitable for smelting by ordinary techniques. Since the black sandstypically contain about 50 percent by weight or less of magnetite and asmuch as twelve or fifteen percent by weight of titanium oxide (rutile),they are not suitable for direct smelting.

Many hundreds of thousands of dollars have been lost in the UnitedStates and abroad attempting to devise techniques for recovering ironore from black sands. Unfortunately, the crystals of rutile are embeddedand interlocked with the crystals of magnetite in the individual sandparticles by reason of the origin of the black sands as igneous ormetamorphic rocks containing both types of crystals. Usually a sandparticle contains only one or two of each type of crystal together withother gangue crystals. Although there are some sand particles which aresolely magnetite crystals, attempts at magnetic separation have beenunsatisfactory because the sand particles containing interlockedmagnetite and rutile crystals are also separated, and the titanium inthe rutile crystals is again present. This problem is furthercomplicated by the fact that the rutile crystals are attracted bymagnetic separators, although rutile exhibits a magnetic attractionabout onethird that of magnetite. The black sands further typicallyinclude other gangue material, such as silica or quartz (SiO andilmenite -(FeTiO which is embedded in and mechanically attached to themagnetite and rutile crystals. It should benoted that ilmenite containsiron and titanium in a single chemically bonded crystal while magnetiteand rutile are separate crystals that are mechanically held together.The ilmenite crystals are also unsuitable for direct smelting byconventional techniques because of their titanium content.

Atleast two types of approaches have been taken in the past inattempting to recover useful mineral ores from the black sands. First,iron smelting techniques and apparatus have attempted to be developedwhich can tolerate the impurities and contaminants found in the blacksands, with these impurities and contaminants being reduced to someextent by magnetic ore concentration of separation apparatus and furtherreduced as part of the smelting process. Secondly, attempts have beenmade to separate the magnetite crystals from the remaining ganguematerial by mechanical techniques such as crushing the particulate blacksands. The crushing approach has been found to have strong economicdisadvantages, and additionally and more importantly, crushing causesrelatively indiscriminate fracturing of the sand particles so as toeffect a mere reduction in size and not separation of magnetite crystalsfrom rutile, silica or other gangue crystals. Moreover, a reduction insize of the magnetite crystals is often undesirable since it may resultin vaporization of the small particles upon smelting or the need forpelletization prior to smelting.

It is further known that the black sands include trace amounts ofvaluable metals such as gold, platinum, rhodium and silver. Priorprocessing techniques and apparatus have not found a suitable way ofrecovering these metals from the black sands. Instead, they act ascontaminants and their value is lost during attempts to smelt the ironore. The result is that these otherwise valuable metals are disregardedas having no value or a negative value in connection with attempts toprocess black sands.

Accordingly, it is an object of the present invention to provide aprocess and apparatus for the recovery of iron ore from black sands withsuch iron ore being suitable for use in conventional iron ore smeltingapparatus.

It is a broader object of the present invention to provide a process andapparatus for breaking the mechanical bonds betweenrelativelyinterlocked and embedded one crystals and gangue crystals toenable separation of the ore crystals for subsequent use of the same.

It is another object of the present invention to provide aprocess andapparatus for the recovery of the mineral ore crystals from particulaterock material which is adaptable for use while the rock material isimmersed in a liquid medium, and particularly salt water, in which it iscommonly found in nature.

It is an additional object of the present invention to provide a processand apparatus for the recovery of a mineral ore from rock material whichwill require little or no treatment of the rock material prior to entryinto the recovery apparatus, will effect recovery of the mineral ore inone continuously operating process, employs virtually no movingmechanical parts, and is readily adaptable to a multitude of orerecovery environments.

It is still a further object of the present invention to provide an orerecovery process and apparatus which will not harm wild life whichpasses through the system,

destroys harmful bacteria found in the waters passing through thesystem, and can be used to reduce undesirable build-ups of sand andparticulate matter at the mouths of streams, rivers and bays.

It is still a further object of the present invention to provide an orerecovery process and apparatus for the same which enables anecologically more efficient means of recovering and utilizing valuabletrace minerals found in composite mineral ore deposits.

Still a further object of the present invention is to provide anapparatus and process for the separation of intermixed but relativelyunbonded ferromagnetic particles from non-ferromagnetic particles inwhich the purity and efficiency of the separation of the particles isenhanced.

It is a further object of the present invention to provide a mineral orerecovery process and apparatus having great versatility of operation toaccommodate changing processing conditions and an economy of operationsuitable for processing hundreds of thousands of tons of material.

The process and apparatus of the present invention have other objectsand features of advantage which will become more apparent and are setforth in more detail in the drawings and description containedhereinafter.

SUMMARY OF THE INVENTION The process of the present invention includes,briefly, irradiating a rock material containing ore and gangue crystalswith ultrasonic waves having a frequency selected to cause one of theore crystals and gangue crystals to vibrate at about a resonantfrequency thereof, with irradiation being maintained until fracturing ofthe rock material occurs at about the interfaces between the crystals;and separating the ore crystals from the gangue material. The amplitudeof the ultrasonic waves is preferably maintained below a level requiredto cause fracturing or internal fatiguing of the mineral ore crystals toprevent a reduction in the size thereof. Irradiation at a frequency inthe range of about 300,000 to about 1,200,000 cycles per second inpreferred, with a frequency of about 750,000 cycles per second beingemployed to separate magnetite ore crystals from rutile and other ganguecrystals. A magnetic ore separator or concentrator and process foroperating the same is also provided in which the flow of a moving liquidmedium is controlled and employed with sequentially applied magneticforces to vertically reciprocate ferromagnetic particulate material towash and separate the gangue particles therefrom.

DESCRIPTION OF A DRAWING FIG. 1 is a top plan view of a schematicrepresentation of mineral ore separation apparatus constructed inaccordance with the present invention.

FIG. 2 is an enlarged top plan view of the ultrasonic processing portionof the apparatus of FIG. 1.

FIG. 3 gives an enlarged, fragmentary, top plan view of a section of theultrasonic processing apparatus of FIG. 2.

FIG. 4 is an enlarged, fragmentary, side elevational view of themagnetic separator portion of the apparatus of FIG. 1.

DESCRIPTION OF THE PREFERRED EMBODIMENT The process of the presentinvention is briefly comprised of breaking the mechanical bonds betweenrelatively interlocked and embedded ore crystals and gangue crystals byshearing or fracturing these crystals apart at the interfacestherebetween through the use of ultrasonic waves. More particularly, aprocess which is economically feasible and highly advantageous has beenfound for the separation of magnetite crystals from rutile and othergangue crystals as contained in black sands rock material. It is knownthat magnetite and rutile have a substantially differingcrystallography. This difference in crystallography affords a basis forseparation of the relatively embedded and interlocked crystals, namely,irradiation of the rock material with ultrasonic waves having afrequency selected to cause one of the mineral ore crystals and thegangue crystals to vibrate at about a resonant frequency thereof. Asused herein, the expression a resonant frequency shall include thefundamental frequency or any harmonic frequency of the fundamentalfrequency. While a selected one of the crystals is in fundamental orharmonic resonance .under the irradiation of ultrasonic waves, theremaining crystals, because of their different crystallography, remainrelatively stationary. The remaining crystals vibrate under theirradiation; however, the size of their oscillations is considerablyless than the crystals in resonance. There, therefore, exists a relativenode condition at the interface between the resonating andnon-resonating crystals, and the'irradiation can be maintained untiloscillations in the resonating crystals are large enough to causefracturing of the rock material at about the interfaces between thecrystals where the node condition occurs.

Ultrasonics have been employed previously in such fieldsv as cleaningand degreasing; the formation of emulsions, including the floatation ofmineral ores to effect separation thereof; fatigue testing; and drillingof various materials including metals. Many of these processes dependupon the phenomenon of cavitation in a liquid medium, that is, therarefaction that occurs in a liquid medium immediately behind atraveling ultrasonic wave. Thus, in U.S. Pat. No. 2,907,455, ultrasonicwaves are used to cause cavitation and agitation in a slurry containingcarbonaceous fuel particles to effect coagulation and recovery of thesame from the slurry. In a similar manner, cavitation may be employed tolift grease and other contaminants ofi of surfaces, to emulsify andsuspend materials in solution, and even to generate a food or a liquidfountain. While cavitation occurs in the process of the presentinvention, it is believed to have only secondary significance.Similarly, in connection with the use of ultrasonic irradiation toeffect fatigue testing and/or drilling, the ultrasonic waves are useddirectly or indirectly to fatigue the crystals and cause internalfracturing and failure thereof. In fatigue testing the crystals ofsubstantially homogeneous materials are simply irradiated until theyfatigue at the weakest point thereon or the point of greatestirradiation intensity. In connection with drilling, abrasives are drivenby the ultrasonic waves and caused to impinge upon a homogeneousmaterial with the abrasives and the waves combining to destroy thecrystalline structure in the path of the ultrasonic beam. The process ofthe present invention does not depend upon such a fatiguing ordestruction of the rock crystals to effect separation of the mineral orefrom the gangue material.

Instead the mechanism for severing the mechanical bonds betweeninterlocked crystals depends on the concept that all crystals willoscillate in free vibration at a frequency peculiar to the dimensionalcharacteristics of the individual material. When forced vibrations atabout the same frequency as the fundamental frequency or a harmonicfrequency of the crystal are impressed upon the crystal, free vibrationsin the crystal are enforced and relatively large oscillations result.

It is, therefore, an important feature of the present invention toirradiate the crystals at a resonant frequency of one of them, andpreferably at the fundamental frequency, to minimize the power requiredto obtain oscillations of a magnitude sufficient to cause fracturing atthe crystal interface.

By amplifying the forced vibrations sufficiently the molecular activityof the crystals can be increased to a destructive level. It is notnecessary, however, to increase the. amplitude of the crystals vibrationto the point that will cause internal destruction of the crystal itself.In the situation in which dissimilar crystals are to be sheared apart,the resonating crystal is mechanically bonded to a dissimilar crystal,and the internal sympathetic vibrations in the resonating crystal willcause shear forces at the interface with the dissimilar nonresonatingcrystal before internal fracturing of the resonating crystal takesplace. It is probable that the cavitation produced in the liquid mediumin which the crystals are placed by the high intensity ultrasonic waveshelps separate the crystals once the mechanical bond is broken orreduces the size of the oscillations required to effect fracturing byimpacting the particles containing the crystals. Additionally,cavitation may impact the sand particles and loosen contaminants, suchas trace amounts of gold, silver, zirconium, and the like, whichcontaminants adhere to the sand or crevices therein but are notmechanically bonded in the same manner as would occur in igneous ormetamorphic rock.

Magnetite (Fe O has an isometric crystallographic system with thecrystals usually taking a hexoctahedral, octahedral, .or dodecahedronform. By contrast, rutile (TiO has a tetragonal crystal system in whichthe crystals are ditetragonal-dipyramidal in form, and they frequentlyoccur in elbow twins and are slender and acicular. Additionally, quartz(SiO crystals fall into the rhombohedral division of the hexagonalcrystal system and take the form of trigonal trapezohedrons andhexagonal trapezohedrons and are commonly prismatic and twinned. As willbe apparent, therefore, the crystallography of the three mainconstituents of black material indicates substantial differences in thecrystal structure. These differences result in a substantial differencein the natural resonant or fundamental frequencies of the respectivecrystals, which differences can be and are employed in the process andapparatus of the present invention.

As also will be understood from the foregoing, crystals of materialsother than magnetite and rutile, which are embedded in each othermechanically, such as in the formation of igneous or metamorphic rock,can similarly be separated. The crystallography of such crystals can bedetermined and used to calculate the natural or fundamental frequenciesof the crystals, or the natural frequencies can be impericallydetermined.

Differences in natural or fundamental frequency will occur whenever thematerials are not the same. Once known, dissimilar fundamentalfrequencies will allow selective sympathetic vibration of one crystal,but not the other.

It should be noted further that as used herein, mineral ore crystalsshall mean the crystals of the material which are primarily soughtafter, and gangue crystals shall means the crystalline material ofsecondary or perhaps no commercial significance. In the separation ofblack sands, for example, the magnetite crystals are commonly referredto as themineral ore crystals and rutile crystals are gangue crystals,notwithstanding the fact that rutile is itself a valuable mineral orewhich can be of substantial economic significance. As will be seen inmore detail hereinafter, it is contemplated in the process of thepresent invention that the rutile and other mineral ores which areseparated from the magnetite be collected and recovered for theirsubstantial eco nomic value. Part of the recovery process for rutilemight include ultrasonic irradiation, in which situation the rutilewould be the mineral ore crystals and quartz might be regarded as ganguecrystals.

Referring now to FIGS. 1, 2 and 3, the ultrasonic processing apparatuscan be seen to include a treatment flow channel 31 and a separation flowchannel 32, preferably axially aligned and interconnected to allowcontinuous treatment and separation of mineral ore. Treatment flowchannel 31 is formed with an inlet opening 33 defined by conduit 34.Extending from conduit 34 is a splitter section 36 of the treatment flowchannel which is formed with partitions or baffles 37, 38 and 39 todivide and separate the flow of incoming material into four'sub-channels41-44. Greater or fewer subchannels can be provided within the scope ofthe present invention, depending upon the flow of the materialprocessed. The mainbody 46 of flow treatment channel 31 acts as anultrasonic cracking chamber and is provided with a plurality ofultrasonic wave generating means 47 arranged in banks along the sidewalls of the partitions which define the sub-channels 4l44. Finally,flow treatment channel 31 may be provided with an end section 48 whichis used to control the speed of the flow of material discharged from theultrasonic cracking chamber, and section 48 tenninates in dischargeopening 49.

In the configuration shown in the drawings, flow control section 48 isconverging to increase the flow rate of the material passing out of thecracking chamber in accordance with the basic law of hydraulics that QAV, where Q represents the quantity of liquid, A represents thecross-sectional area of the conduit or channel, and V represents thevelocity of the liquid. While it is possible to vary Q the pumping meansor the like, for any given Q separator section 32 in the preferredconfiguration is more effective if velocity is increased over that inthe ultrasonic treatment section.

When processing a sand or gravel, the apparatus is preferably furtherprovided with pump means 51 connected to conduit 34 in orderthat amixture of the particulate material and a liquid, such as salt water,may be pumped through treatment flow channel 31 for ultrasonicirradiation. Large deposits of black sands, for example, are often foundimmersed in salt water. Fortunately, salt water is one of the bestliquid mediums in which to propagate and transmit ultrasonic waves. Inthe process of the present invention, therefore, pump 51, which ispreferably a jet pump, can be attached to a suction line 52 to drivesand and salt water up to the processing apparatus. The ultrasonictreatment channel 31 and separation channel 32 are preferably positionedon a floating barge anchored above the sand deposit.

In order to enhance the effectiveness of the ultrasonic irradiationinseparating crystals, it is preferred that an ultrasonic wavereflecting means 53 (FIG. 3) be positioned on a side opposite the flowtreatment subchannel, such as sub-channel 44, from the probe 54 of theultrasonic wave generating means. As shown in the preferred form,reflective means 53 is a parabolic reflector joined at the edges 56 and57 with the side walls of partition 37 so as to present a smooth flowchannel which will not impede or trap particles. Reflector S3 isemployed to increase the field strength in sub-channel 44. As will beseen by the broken lines in FIG. 3, the parabolic reflector results in areflected wave pattern which reinforces the wave pattern emanatingdirectly from probe 54. It is also possible to provide a secondelectronic generating wave transducer positioned opposite transducer 47with a probe extending through reflector 53. This second transducercould be used with a second parabolic mirror positioned in front oftransducer 47 with the result that the particulate liquid slurry ormixture would be subjected to very high intensity irradiation fromopposed transducers.

In order to insure complete cracking of the sands into constituentcrystals, variation of the frequency of the ultrasonic waves may berequired. It is, therefore, preferred that the transducer or wavegenerating means 47 be driven by a signal generator 58 capable ofvarying the frequency of the ultrasonic waves produced by thetransducer. For the separation of most interlocked mineral crystals,ultrasonic waves in the range of about 300,000 to about 1,200,000 cyclesper second can be employed to effect fracturing at the interfacesbetween the crystals. The best results occur and the least power isrequired when the frequency is selected in the above range so as tocause one of the crystals to vibrate at about a resonant frequencythereof. When black sands material is being treated, the ultrasonicwaves are preferably selected to have a frequency of between about700,000 to 800,000 cycles per second, with about 750,000 cycles persecond being optimum to cause the magnetite crystalsto resonate andbecome sheared and fractured with respectto the rutile crystals.Alternatively, however, signal generator 58 can be adjusted to drivetransducer 47 at a frequency in the range of between about 1,000,000 and1,200,000 cycles per second so as to cause the rutile crystals toresonate and to shear away from the relatively stationary magnetitecrystals. In some configurations the transducer electronics or geometrymay have to be modified to get the full range of frequency adjustment.When the rutile crystals are selected, they constitute the mineral orecrystal as used herein and the magnetite crystals, although quitevaluable, constitute the gangue crystal material.

Black sands have the advantage of being of relatively uniform andconsistent size, making adjustments in frequency less necessary thanmight be required for other materials. Some adjustment of the resonatingfrequencies, however, may be required by reason of the composition ofthe black sands being processed, as well as the volume and the flow rateof the liquid passing in front of the transducer. A single signalgenerator and amplifier unit 58 will accommodate such variations and canbe used to drive a multiplicity of transducers, such as are contained inthe banks of transducers shown in the drawing. It is further possible touse multiple signal generators to drive banks of transducers atdiffering frequencies simultaneously to cover the range in which allsand particles will be effectively treated.

It is preferred to employ a magnetostrictive ultrasonic transducer sincethese devices are relatively rugged. Piezoelectric transducers can alsobe employed and may have certain advantages at high frequencies. Bothtypes of transducers are commercially available as are signal generatorsand amplifiers for driving multiple transducers. Signal generating means58 are also available which will allow variation of the power andaccordingly the amplitude of the ultrasonic waves impinged upon the rockmaterial.

As above noted, it is usually preferable that the fracturing of the rockmaterial by ultrasonic waves take place in a manner which maintains theparticle size of the mineral ores as large as is possible. Maintainingthe particle size enables direct smelting without pelletization.Therefore, the separation process will eliminate a pelletizing step aslong as the amplitude of the ultrasonic waves are below the amplituderequired to cause fracturing and a substantial reduction in size of themineral ore crystals. It should be noted that some sand particles willcontain more than one mineral ore crystal. Ultrasonic irradiation ofthese particles will usually sever the similar as well as the dissimilarcrystals, and thus, some particle size reduction will occur in additionto that resulting from severing of the rutile or gangue crystals.Sampling of the end product from the apparatus of the present inventioncan be used to determine variation of the power at signal generator 58and transducer 47. When black sands are being irradiated at 750,000cycles per second, fracturing at the interfaces will occur almostinstantaneously as the sand passes in front of the transducers in a 24inch wide treatment channel without internally fracturing the crystals.

in certain situations, steel processing plants are constructed in amanner which will only accept pelletized ore of substantial size.Accordingly, in these situations, it may be advantageous to not onlyfracture the magnetite ore from the rutile and other gangue crystals,but to fracture the magnetite crystals themselves so as to facilitatesubsequent pelletizing. If this is desired, the amplitude of theultrasonic waves can be increased until the sympathetic vibration withinthe crystals, as well as the cavitation, is substantial enough to causeinternal fracturing of the crystals and to effect a reduction of thesize of the crystals for their use in pelletized applications.

The pump 51 and probes 54 are the only apparatus which will requireperiodic maintenance or replacement, since the ultrasonic treatmentchamber is substantially free of moving parts. Abrasion of thetransducer probes by the sand and cavitating salt water will eventuallycause destruction of the probes. Since extremely hard materials erode ata higher rate, it is preferable that probes be constructed of an erosionresistant material such as molybdenum steel. It should also be notedthat instead of a pump 51, the mixture of liquid and rock can be urgedby gravity through the separator system of the present invention.

In order to insure fracturing of the rock material, it is possible toirradiate the rock with ultrasonic waves simultaneously from twoultrasonic wave generating means which have differing frequencies. Thus,adjacent transducers can be formed with overlapping fields of ultrasonicwaves with one generator irradiating at a first frequency and a secondor additional generator irradiating ultrasonic waves at a second anddifferent frequency. The impressing of a first frequency on the rockmaterial which causes the selected crystal to vibrate at about itsnatural frequency and simultaneous impressing of a second differingfrequency may be used to enhance the cleavage and fracturing betweencrystals. While side-by-side generators can be employed, it is alsopossible to position the second transducer directly across from thefirst in a manner similar to that described above in connection withintensifying the power in the treatment channel.

While it is believed that the primary mechanism inv volved in separatingthe crystals is sympathetic vibration of a selected crystal, undoubtedlythe substantial cavitation produced in the sub-channels 41-44 enhancesperformance. The cavitation insures circulation of the particulate sandthrough the ultrasonic field so as to expose the same to irradiation.Moreover, the cavitation will act to clean the severed crystals ofcontaminants which are deposited in crevices or adhered to the crystalsurfaces.

It should be noted further that an important advantage and feature ofuse of the ultrasonic process is that it is accompanied by a verybeneficial ecological effect. The waters in many alluvial plane areashave become contaminated and polluted by raw sewage discharged fromnearby population centers. The sands have been deposited to a degreethat the flow of the rivers discharging into the ocean are notsufficient to carry away the sewage. Accordingly, it becomes a stagnantbreeding ground for serious infectious diseases, including even typhoidfever. The highenergy bombardment in the cracking chamber 31 of theprocess of the present invention beneficially destroys bacteriacontained in the waters passed through the system. Thus, the processingof substantial volumes of water and sand (for example a flow rate of4,000 gallons per minute) results in a removal of bacteria whichameliorates the health hazard. Additionally, the removal of sand fromthe mouth of the river further enhances the surge of the river toenablecarrying waste products away from the populated areas; andthe'removal .of sand will afford improved access to the rivers formigrating fish, such as salmon.

The type of mineral crystal separated by ultrasonic irradiation insection 31 will determine the'type of concentrating, segregating orseparating apparatus into which the severed particulate crystals aredischarged through discharge opening 49. if the mineral crystals arenon-magnetic, sophisticated and effective 96-stage sluice systems can beemployed to selectively gradeand separate ores such as titanium, thenoble metals, zirconium and silica. In connection with the extraction ofmagnetite from black sands material, however, the magnetite crystals arehighly ferromagnetic andv yet have a density making them difficult toseparate in a multiple stage sluice gate system. It is, therefore, ad-

vantageous to employ a ferromagnetic separator or concentrator inconnection with the ultrasonic processor above described. v

The use of magnetic separators orv ore concentrators is well known andhasbeen employed in connection with the separation of magnetiteandrutile. One approach is exemplified by US. Pat. Nos. 1,425,235 and3,552,564 in which ferromagnetic ore is passed underneath a plurality ofmagnets which have cycling magnetic fields to enable movement of the oreunder the influence of gravity and escape of the non-ferromagneticgangue material. In these systems the ore is held against aplate by themagnets, and the gangue falls in 'air away from the ore to collectingbins. The magnetic forces are maintained so as to hold the ferromagneticore against the plate except during short intervals which allows the oreto slip down along the plate to an ore concentration zone. Similarapproaches are shown in US. Pat. Nos. 871,301, 871,365 and 2,975,897. Itshould be noted that dry processing techniques are not well suited foruse with black sands material which is immersed in water since itrequires an extra drying step. A drying step usually requires heating,if it is to be accomplished within a reasonable period of time, andheating black sand material may give rise to a very un desirable sideeffect. Both rutile (TiO and ilmenite (FBTiOg), when heated enough todry them out, undergo a substantial increase in magnetism, and they willbe magnetically indistinguishable from magnetite and will be gathered upwith the magnetite. Since both rutile and ilmenite contain titanium, thetitanium will once again make the iron ore unsuitable for smelting. Bycontrast, however, if the rutile and ilmenite are kept wet and cold,they will exhibit a magnetic attraction about one-third that ofmagnetite. Thus, magnetic separation processes which require dryparticles, which in turn require heating of the particles to dry thesame,-

will be unsuitable for the separation of the magnetite crystals fromblack sands containing rutile and ilmenite.

Wet magnetic separators have also been employed to separate particulateferromagnetic mineral ores. Typical of this approach are US. Pat. Nos.2,714,960 and 3,289,836. The apparatus disclosed in these patentsincludes a rotating or movable magnetic field which travels in adirection counter to the direction of flow of a washing liquid. Whilehaving certain advantages, such systems are susceptible to clogging,require a multiplicity of moving parts and attendant maintenanceproblems, andhave hydraulic systems which are more difficult tointegrate with the flow from an ultrasonic processing or crackingchamber.

Referring now to FIG. 4, the magnetic separating stage 32 of theapparatus of the present invention and the process implementedtherebycan be set forth in greater detail. As will be seen, reducingsection 48 of the ultrasonic treatment channel is connected to an inletopening 61 in separation flow channel 32. It should be noted again thatFIG. 4 is a side elevational view as opposed to the top plan view ofFIGS. 1 and 2. Positioned superjacent flow channel 32 are a plurality ofmagnetic force generating means 62 formed for application of magneticforces to the mixture of liquid medium and particulate ore and ganguematerial as the mixture passes beneath the magnetic force generatingmeans. Flow channel 32 is formed adjacent a second end thereof withub-channels 63 and 64, with channel 63 acting as an ore receivingportion of the apparatus and channel 64 acting as a gangue receivingportion. As indicated by the arrows, the liquid mixture and particulatematerials flow from inlet opening 61 toward ore receiving portion 63 andgangue receiving portion 64.

As will be seen, thelower surface 66 of separation channel 32 divergesfrom the upper surface 67 with the resultant progressive increase in thearea of the flow channel from the inlet to the ore and gangue receivingend thereof. In accordance with the basic laws of hy draulics, theincoming velocity of the mixture of liquid medium and particulatematerial will be relatively high and will gradually decrease as themixture moves through the separation channel. As will be understood, thedecrease of flow rate of the liquid will tend to cause gravitationalsettling of the particulate materials as the liquid progresses towardthe gangue and ore receiving portions. Similarly, the motion of theliquid will have a component which tends to urge or propel theparticulate material toward the ore and gangue receiving portions. It isalso possible to enlarge the area of channel 32 in the horizontaldimension to effect a reduction in velocity of the carrier liquidmedium, but this type of approach requires a widening of the magneticfield, which may be disadvantageous. Additionally, the downwardlysloping surface 66 insures movement of the gangue material towardportion 64 under gravitational forces, whereas a fiat bottomsurface 66would have to depend solely on the flow of liquid through the separationchannel to move the gangue material. Similarly, upper surface 67 couldbe upwardly sloped to effect a reduction in velocity, but this canresult in turbulence at the upper surface which would interfere to somedegree with the matnetic attraction.

In order to effect separation of the ferromagnetic particles from theparticulate non-ferromagnetic gangue, magnetic force generating means 62are connected by conductors 68 to a controller 69, which may be used toapply and terminate (including a nulling of the hysteresis effect) themagnetic forces generated by the generating means intermittently atdiscrete, relatively spaced apart intervals along flow channel 32. Suchcycling of the magnetic forces alternatively and repetitively attractsthe ferromagnetic particles toward the magnetic force generating meansand release the same to fall under the influence of gravity. in theferromagnetic particle separator of the present invention, the magneticforces are applied and then tenninated progressively in the samedirection as the flow of the liquid medium in channel 32. Magnetic forcegenerating means 62 is advantageously comprised of a plurality ofside-by-side electromagnets, each formed for independent actuation andconnected to controller 69. in operation, controller 69 will activatemagnet 71 for a first period of time. Thereafter, the controllerdeenergizes magnet 71 and nulls the same by a nulling coil toeffectively terminate the magnetic forces generated, including themagnetic flux remaining in the magnet due to the hysteresis phenomenon.There no longer being a lingering magnetic field in or about magnet 71,the ferromagnetic particles will begin to fall back toward surface 66away from magnet 71 while being carried downstream by the velocity ofthe liquid mixture. At about the termination of magnet 71, magnet 74 isactivated by the controller and begins to draw the ferromagneticparticles back up toward magnet 74. Momentarily, magnet 74 isde-energized and nulled, and the particles again gravitate downwardly inthe liquid medium until magnet 77 is activated and begins to pull theferromagnetic particles upwardly in the liquid medium. This sequence isrepeated for magnets 80, 83 and 86. Upon activation of magnet 77,however, the controller further activates magnet 72 and begins anotherprogressive sequence with magnets 72, 75, 78, etc. Similarly, uponactivation of magnet 83 and magnet 78, a third series of magnets,beginning with magnet 73, is progressively and sequentially activatedand terminated by controller 69. The third series includes magnet 73,76, 79, etc. 1

Thus, the ferromagnetic ore is repetitively drawn up toward anelectromagnet, allowed to settle and gravitate back down in the movingliquid medium towards the bottom of the flow chamber and then raisedupwardly again by the magnets. The sequencing of magnets insures thatthere is always at least one deenergized and nulled magnet between anytwo energized magnets. In this manner the ferromagnetic particlesflowing downstream in the flow channel are never drawn in a backwarddirection contrary to the flow. The magnetic action keeps theferromagnetic material and, particularly magnetite ore, close to the topof separator channel 32, while repeatedly washing the ore upwardly anddownwardly transverse to the stream flow to allow trapped ganguematerial to be washed from the ferromagnetic particles. This washingtechnique, however, makes use of the flow of the liquid mixture to urgeboth the magnetic and non-magnetic particles toward the respectivecollecting portions 63 and 64. The washing effect is particularlydesirable so as to clean the ore to as high a degree as possible forblast furnace use. The on-off' action of the magnets further insuresthat the separator channel 32 does not become clogged with particulatematerial.

Beginning adjacent ore receiving sub-channel 63, it is possible to cyclethe magnets more frequently to keep the magnetic ore in a tightgrouping. For example, magnets 87, 88 and 89 can be energized,de-energized and then nulled one after the other without any deenergizedmagnets therebetween. Additionally, the magnetic flux can beprogressively reduced adjacent ore receiving portion 63 to allow theless magnetically responsive rutile and ilmenite to escape the magneticflux and fall down with the non-magnetic gangue. The reduction in fluxof magnets in portion 63 also allows the ore to fall free of themagnetic field for conveyance to a ferromagnetic ore stockpile.

The gangue material will initially be suspended and intermixed with theferromagnetic ore at inlet opening 61. The turbulence resulting fromreciprocation of the ferromagnetic materials and the velocity of theliquid will maintain the gangue in suspension for a period of time whichinsures that the gangue will not trap an undue quantity of theferromagnetic particles and gravitate them to the bottom of theseparation channel. As the velocity slows, turbulence will decrease, andthe gangue will begin gravitating toward surface 66 of the flow channeland will be urged toward the gangue receiving portion.

It is a further feature of the present invention to form an uppersurface of the sub-channel 64 to converge toward lower surface 66 so asto increase the velocity of the liquid in gangue receiving channel 64.The increase in velocity of the liquid causes the gangue to again bepicked up and maintained in suspension in the liquid medium so as toprevent the piling up or building up of gangue in the conduit to thegangue stockpile or to a non-ferromagnetic separator, such as sluicegate system. It is also possible to pump additional liquid into theseparating chamber at portions 63 and 64 through nozzles (not shown) toinsure suspension of the particles to prevent clogging.

There are several methods of implementing the control function ofcontroller 69. It is preferable to use bar magnets having coilstherearound, with the number of coils determining the field strength.The number of coils can be varied to obtain a field gradient from end 61to portion 63, or the magnets can be driven at differing levels tochange field strength. Similarly, the effective air gap can be increasedalong the length of the separation chamber to vary field strength. Theelectromagnets may be cooled in a liquid bath (not shown) to preventoverheating. Controller 69 can be used to energize the electromagnets,and then for a short period of time, a nulling coil activated to reversethe polarity in the core and nullify the magnet. This sequence can beaccomplished, for example, electronically, by employing a rotating discwith brushes or rollers, or a photoelectric cell having an element whichinterrupts the light in accordance with the speed at which the magnetsare to be sequenced. The ability to vary the speed of the controllerallows cycling of the electromagnets at different rates to accommodatedifferent flow rates through the separation chamber 32. Thus, if.sampling indicated too much gangue was being carried over to the orereceiving portion or too much ore to the gangue receiving portion, itwould be possible to alter the rate at which the magnetic fieldprogressively moves down the chamber to obtain better separation.

It should be noted further that while a single treatment or ultrasoniccracking chamber and single magnetic separator are shown, it is quitepossible and in some instances advantageous to employ additionalultrasonic cracking chambers, for example, at a location downstream ofgangue receiving portion 64 of the magnetic separator. Similarly, itwould be possible to again irradiate the materials deposited in orereceiving channel 63 with ultrasonic waves followed by a second magneticseparation to obtain even cleaner ore. Moreover, ultrasonic irradiationof the gangue material traveling down channel 64 could also be selectedto insure fracturing of different materials such as the rutile fromsilica or other gangue crystals. One of the important advantages of theore recovery system of the present invention is, therefore, that it issusceptible to sequential or series positioning of cracking chambers andseparators for continuous flow-through processing of ore.

I claim:

1. A process for breaking the mechanical bonds between relativelyinterlocked and embedded mineral ore crystals and gangue crystalscontained in a rock material, said crystals having differing fundamentalresonant frequencies, to enable separation of said mineral ore crystalsfrom said gangue crystals, comprising:

irradiating said rock material with ultrasonic waves having a frequencyselected to cause one of said mineral ore crystals and said ganguecrystals to vibrate at about a resonant frequency thereof, saidirradiation being maintained until fracturing of said rock materialoccurs at about the interfaces between said crystals.

2. The process as' defined in claim 1 wherein,

said rock material is selected to contain magnetite ore crystals andrutile gangue crystals.

3. The process as defined in claim 2 wherein, said rock material isblack sand.

in size of a substantial quantity of said mineral ore crystals.

6. The process as defined in claim 1 wherein, v said irradiating step isaccomplished by irradiating with ultrasonic waves having an amplitudeabove the amplitude required to cause fracturing of a substantialquantity of said mineral ore crystals to effect reduction in the sizethereof.

7. The process as defined in claim 1, and

simultaneously with said irradiating step, subjecting said rock materialto ultrasonic waves from an additional source, said ultrasonic wavesfrom said additional source having a frequency selected to differ fromthe frequency of said ultrasonic waves of said irradiating step.

8. A process for recovery of a mineral bearing ore from rock containingmineral ore crystals interlocked with and embedded in a gangue materialcomprising:

a. irradiating said rock with ultrasonic waves having a frequency in therange of about 300,000 to about 1,200,000 cycles per second untilfracturing occurs at the interfaces between said mineral ore crystalsand said gangue material in a substantial quantity of said rock; and

b. separating said mineral ore crystals from said 11. The process asdefined in claim 10 wherein,

said frequency is selected to be about 750,000 cycles per second.

12. The process as defined in claim 8 wherein,

said mineral ore crystals are magnetite and said gangue materialincludes rutile, and said ultrasonic waves have a frequency in the rangeof between about 1,000,000 and 1,200,000 cycles per second.

13. The process as defined in claim 8 wherein,

said rock is selected as black sands containing magnetite ore crystalsand rutile gangue material, and said rock material is immersed in saltwater.

14. A process for recovery of a mineralbearing ore as defined in claim 8wherein,

said mineral ore crystals are ferromagnetic and said gangue material issubstantially less magnetic than said mineral ore crystals; and

said separating step is accomplished by:

' i. introducing a mixture of said mineral ore crystals and said ganguematerial and a liquid medium into a separation apparatus through aninlet portion in a first end thereof, said separation apparatus havingan ore receiving portion and a gangue receiving portion adjacent asecond end thereof with said ore receiving portion positioned above saidgangue receiving portion;

ii. urging said liquid medium to flow from said inlet portion to saidore receiving portion and said gangue receiving portion;

iii. intermittently applying a vertically oriented magnetic force tosaid mixture from a position above said mixture and terminating'saidmagnetic force to repetitively move the ferromagnetic mineral orecrystals upwardly through said liquid medium; and

iv. allowing both said ferromagnetic mineral ore crystals and saidgangue material to gravitate downwardly through said liquid medium whilesaid magnetic force is terminated, said magnetic force being appliedwith a frequencycausing said ferromagnetic mineral ore crystals to bemaintained in the upper portion of said mixture as said mixture reachessaid gangue and said ore receiving portion for deposit of saidferromagnetic ore crystals in said'ore receiving portion.

15. The process for recovery of a mineral bearing ore as defined inclaim 14 and the step of:

reducing the rate of flow of said liquid medium as said liquid mediumprogresses from said inlet portion to said ore receiving portion andsaid gangue receiving portion.

16. A process for recovery of a mineral bearing ore as defined in claim14 wherein,

said separation apparatus includes a plurality of magnetic forcegenerating means positioned in relatively spaced apart relation andextending from adjacent said inlet portion to adjacent said orereceiving portion; and

said magnetic force is applied by each generating means sequentiallycommencing adjacent said inlet portion and progressively applied andthen terminated in a direction toward said ore receiving portion.

17. A process for recovery of a mineral bearing ore as defined in claim16 wherein,

said magnetic force is applied in the following sequence:

a first magnetic force is applied to said mixture by a first generatingmeans while adjacent generating means to said first generating meansapply substantially zero magnetic force to said mixture;

said first magnetic force is terminated and a second magnetic force isapplied to said mixture by second generating means positioned betweensaid first generating means and said ore receiving portion whileadjacent generating means to said second generating means applysubstantially zero magnetic force to said mixture; and

said second magnetic force is terminated and subsequent magnetic forcesare applied to said mixture by subsequent generating means, each saidsubsequent generating means being progressively positioned between thenext preceding generating means applying a magnetic force and said orereceiving portion and said generating means adjacent said subsequentgenerating means apply substantially zero magnetic force to said mixtureduring activation of each of said subsequent generating means. I

18. Apparatus for the formation of a mixture of ferromagnetic ore andnon-ferromagnetic gangue material from rock containing said ore and saidgangue material and for separation of said ore and said gangue materialcomprising:

a. a treatment flow channel having an inlet opening for receipt of rockcontaining said ore and said gangue material, said treatment flowchannel being adapted for receipt and flow of a liquid mediumtherethrough and having a discharge opening communicating with an inletopening in a separation flow channel; v

b. ultrasonic wave generating means positioned adjacent said treatmentflow channel intermediate said inlet and discharge openings and formedfor'irradiation of said rock with ultrasonic waves while immersed insaid liquid medium and positioned in said treatment flow channel;

. a separation flow channel formed to contain said liquid medium, saidore and said gangue material therein, said flow channel being-formedwith an inlet opening at a first end thereof communicating with saiddischarge opening in said treatment flow channel and terminating in anore receiving portion and a gangue receiving portion adjacent a secondend thereof;

d. means for causing said liquid medium to flow through from saidtreatment flow channel and said separation flow channel to said ore andgangue receiving portions operatively connected to said separation flowchannel;

. magnetic force generating means positioned superjacent said flowchannel and formed to apply magnetic forces to said ore and ganguematerial as immersed in said liquid medium and positioned in said flowchannel, said generating means being further formed to apply andterminate said magnetic forces intermittently at discrete intervalsalong said flow channel intermediate of said inlet opening in saidseparation flow channel and said ore receiving portion; and

magnetic control means connected to said magnetic force generating meansand formed to repetitively cause said magnetic generator means to applyintermittent magnetic forces at discrete intervals along said separationflow channel progressively in a direction from said inlet openingtherein to said ore receiving portion.

19. Apparatus as defined in claim 18, and

pump means connected to urge said rock and liquid medium from said inletopening through said treatment flow channel and to said dischargeopening and through said separation flow channel; and ultrasonic wavereflecting means positioned on a side opposite said treatment flowchannel from said ultrasonic wave generating means and formed and"treatment flow channel toward said ultrasonic wave generating means.

2. The process as defined in claim 1 wherein, said rock material isselected to contain magnetite ore crystals and rutile gangue crystals.3. The process as defined in claim 2 wherein, said rock material isblack sand.
 4. The process as defined in claim 3 wherein, saidirradiating step is accomplished while said black sand is immersed in aliquid, and said frequency is selected to cause said magnetite crystalsto vibrate at about a resonant frequency thereof.
 5. The process asdefined in claim 1 wherein, said irradiating step is accomplished byirradiating with ultrasonic waves having an amplitude below theamplitude required to cause fracturing and a substantial reduction insize of a substantial quantity of said mineral ore crystals.
 6. Theprocess as defined in claim 1 wherein, said irradiating step isaccomplished by irradiating with ultrasonic waves having an amplitudeabove the amplitude required to cause fracturing of a substantialquantity of said mineral ore crystals to effect reduction in the sizethereof.
 7. The process as defined in claim 1, and simultaneously withsaid irradiating step, subjecting said rock material to ultrasonic wavesfrom an additional source, said ultrasonic waves from said additionalsource having a frequency selected to differ from the frequency of saidultrasonic waves of said irradiating step.
 8. A process for recovery ofa mineral bearing ore from rock containing mineral ore crystalsinterlocked with and embedded in a gangue material comprising: a.irradiating said rock with ultrasonic waves having a frequency in therange of about 300,000 to about 1,200,000 cycles per second untilfracturing occurs at the interfaces between said mineral ore crystalsand said gangue material in a substantial quantity of said rock; and b.separating said mineral ore crystals from said gangue material.
 9. Theprocess as defined in claim 8 wherein, said gangue material iscrystalline and the frequency of said ultrasonic waves is selected insaid range to cause one of said mineral ore crystals and the crystallinegangue material to vibrate at about a resonant frequency thereof. 10.The process as defined in claim 8 wherein, said mineral ore crystals aremagnetite and said gangue material includes rutile, and said ultrasonicwaves have a frequency in the range of between about 700,000 to about800,000 cycles per second.
 11. The process as defined in claim 10wherein, said frequency is selected to be about 750,000 cycles persecond.
 12. The process as defined in claim 8 wherein, said mineral orecrystals are magnetite and said gangue material includes rutile, andsaid ultrasonic waves have a frequency in the range of between about1,000,000 and 1,200,000 cycles per second.
 13. The process as defined inclaim 8 wherein, said rock is selected as black sands containingmagnetite ore crystals and rutile gangue material, and said rockmaterial is immersed in salt water.
 14. A process for recovery of amineral bearing ore as defined in claim 8 wherein, said mineral orecrystals are ferromagnetic and said gangue material is substantiallyless magnetic than said mineral ore crystals; and said separating stepis accomplished by: i. introducing a mixture of said mineral orecrystals and said gangue material and a liquid medium into a separationapparatus through an inlet portion in a first end thereof, saidseparation apparatus having an ore receiving portion and a ganguereceiving portion adjacent a second end thereof with said ore receivingportion positioned above said gangue receiving portion; ii. urging saidliquid medium to flow from said inlet portion to said ore receivingportion and said gangue receiving portion; iii. intermittently applyinga vertically oriented magnetic force to said mixture from a positionabove said mixture and terminating said magnetic force to repetitivelymove the ferromagnetic mineral ore crystals upwardly through said liquidmedium; and iv. allowing both said ferromagnetic mineral ore crystalsand said gangue material to gravitate downwardly through said liquidmedium while said magnetic force is terminated, said magnetic forcebeing applied with a frequency causing said ferromagnetic mineral orecrystals to be maintained in the upper portion of said mixture as saidmixture reaches said gangue and said ore receiving portion for depositof said ferromagnetic ore crystals in said ore receiving portion. 15.The process for recovery of a mineral bearing ore as defined in claim 14and the step of: reducing the rate of flow of said liquid medium as saidliquid medium progresses from said inlet portion to said ore receivingportion and said gangue receiving portion.
 16. A process for recovery ofa mineral bearing ore as defined in claim 14 wherein, said separationapparatus includes a plurality of magnetic force generating meanspositioned in relatively spaced apart relation and extending fromadjacent said inlet portion to adjacent said ore receiving portion; andsaid magnetic force is applied by each generating means sequentiallycommencing adjacent said inlet portion and progressively applied andthen terminated in a direction toward said ore receiving portion.
 17. Aprocess for recovery of a mineral bearing ore as defined in claim 16wherein, said magnetic force is applied in the following sequence: afirst magnetic force is applied to said mixture by a first generatingmeans while adjacent generating means to said first generating meansapply substantially zero magnetic force to said mixture; said firstmagnetic force is terminated and a second magnetic force is applied tosaid mixture by second generating means positioned between said firstgenerating means and said ore receiving portion while adjacentgenerating means to said second generating means apply substantiallyzero magnetic force to said mixture; and said second magnetic force isterminated and subsequent magnetiC forces are applied to said mixture bysubsequent generating means, each said subsequent generating means beingprogressively positioned between the next preceding generating meansapplying a magnetic force and said ore receiving portion and saidgenerating means adjacent said subsequent generating means applysubstantially zero magnetic force to said mixture during activation ofeach of said subsequent generating means.
 18. Apparatus for theformation of a mixture of ferromagnetic ore and non-ferromagnetic ganguematerial from rock containing said ore and said gangue material and forseparation of said ore and said gangue material comprising: a. atreatment flow channel having an inlet opening for receipt of rockcontaining said ore and said gangue material, said treatment flowchannel being adapted for receipt and flow of a liquid mediumtherethrough and having a discharge opening communicating with an inletopening in a separation flow channel; b. ultrasonic wave generatingmeans positioned adjacent said treatment flow channel intermediate saidinlet and discharge openings and formed for irradiation of said rockwith ultrasonic waves while immersed in said liquid medium andpositioned in said treatment flow channel; c. a separation flow channelformed to contain said liquid medium, said ore and said gangue materialtherein, said flow channel being formed with an inlet opening at a firstend thereof communicating with said discharge opening in said treatmentflow channel and terminating in an ore receiving portion and a ganguereceiving portion adjacent a second end thereof; d. means for causingsaid liquid medium to flow through from said treatment flow channel andsaid separation flow channel to said ore and gangue receiving portionsoperatively connected to said separation flow channel; e. magnetic forcegenerating means positioned superjacent said flow channel and formed toapply magnetic forces to said ore and gangue material as immersed insaid liquid medium and positioned in said flow channel, said generatingmeans being further formed to apply and terminate said magnetic forcesintermittently at discrete intervals along said flow channelintermediate of said inlet opening in said separation flow channel andsaid ore receiving portion; and f. magnetic control means connected tosaid magnetic force generating means and formed to repetitively causesaid magnetic generator means to apply intermittent magnetic forces atdiscrete intervals along said separation flow channel progressively in adirection from said inlet opening therein to said ore receiving portion.19. Apparatus as defined in claim 18, and pump means connected to urgesaid rock and liquid medium from said inlet opening through saidtreatment flow channel and to said discharge opening and through saidseparation flow channel; and ultrasonic wave reflecting means positionedon a side opposite said treatment flow channel from said ultrasonic wavegenerating means and formed and positioned to reflect ultrasonic wavespassing across said treatment flow channel back across said treatmentflow channel toward said ultrasonic wave generating means.